I can't believe I didn't bet the under 10.5 here. AZ is 1/9 o/u in their last 10 while Cin is 2-8. Both pitchers have pitched well in their last 3 games after racking up big ERA's in earlier outings.
A lot of people look at the pitcher's alone ERA and judge accordingly.
Over all ERA is important but more important like you said is their last 3-5 outings go as far as their ERA goes! Also I check opponents BA against each pitcher! Very Important.